They trade jokes,chuckle and talk shop about a hacker plot called Project Mayhem.

But at the heart of the conference call between the FBI and Scotland Yard was a strategy aimed at bringing down the hacking collective known as Anonymous,which has launched a series of embarrassing attacks across the Internet. Unfortunately for the cyber sleuths,the hackers were listening,too,and now so is the rest of the world.

Anonymous published the roughly 15-minute-long recording of the call to the Internet early Wednesday,gloating in a Twitter message that the FBI might be curious how were able to continuously read their internal comms for some time now.

The FBI said the information was intended for law enforcement officers only and was illegally obtained but that no FBI systems were compromised. Scotland Yard said that theyd seen no immediate information that their operations had been compromised,but that the force was still checking. The bureau said that a criminal investigation is under way to identify those responsible. Its not entirely clear how the hackers got their hands on the recording,which appears to have been edited to bleep out the names of some suspects.

Amid the material published by Anonymous was an email purportedly sent by an FBI agent to international law enforcement agencies. It invites his foreign counterparts to join the call to discuss the ongoing investigations related to Anonymous. The message contained a phone number and password for accessing the call. The email is addressed to officials in the UK,Ireland,the Netherlands,Sweden and France,but only US and British officials can be heard on the recording.

Graham Cluley,an expert with data security company Sophos,said that hackers must have been able to eavesdrop on the call because they had compromised the investigators emails. The hackers knew the phone number,the time,the passcode, he said.